Impact of Insulating Press board insulation on life of Electrical Transformers

Any electrical transformer is made broadly of two types of components 

1. active parts and
2. non-active parts

Transformer insulation press boards & insulating papers form one of the non-active parts of oil-cooled electrical transformers. By non-active part, it is meant that there is no flow of current or magnetic induction through the components. Generally, the active part of a transformer can be easily tested when the transformer is made. On the other hand, transformer insulation cannot be tested easily. 

Some of the parameters which are important in transformer insulating press boards & insulating papers & which determine the life of it are:

1. Ageing properties: Good quality transformer insulation will be made of the long virgin fibre of softwood found in cold climatic conditions. These long fibres, when formed into insulating pressboard & paper by the wet-laid process, gives a very tight cohesive binding between its layers. As the fibres are virgin, thus their strength is also uncompromised. This insulation material made from such fibres will have excellent ageing properties, resulting in a long life of transformers.
2. The purity of fibres: For manufacturing of economical grade of press boards, a certain quantity of secondary fibres are mixed with virgin fibres. These secondary fibres are shorter in length and thus have lower integrity to insulation structure. Such press boards tend to leach out fibres in transformer oil over a period of time, making it impure. Such impure oil will reduce the life of the transformer as oil gradually loses its own properties of acting as a coolant.
3. Consistency of fibre layering: The main purpose of insulating pressboard is to stop transmission of electricity across itself. It is used in various forms in a transformer – usually spacers, ducts, trapezoidal or key strips, yoke insulation, phase barrier, footplate, cylinders blocks etc. It is important that every component should have consistent fibre layering across it to ensure that there is no weak spot through which electricity passes. This is also known as the breakdown voltage of the insulating material. 

All the above three parameters are extremely important in any transformer insulating pressboard to ensure high life of the transformer. The source of such insulation is very important as these parameters can only be tested in specific laboratories and its impact is only known over a period of time.

We at Pristine Technologies & Industries ensure that only the best quality of Electrical Grade insulating press boards manufactured by ABB India Ltd (Erstwhile Raman Boards Ltd) is used in making of components by us. This results in high life & maintenance-free working of your transformers for long durations. Transformer insulation components manufactured by us can be used in distribution and power transformers from 11 KV class to 132 KV class ratings.  

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